I come from an Open Source background. We share things. We make them available for others to use, adapt, improve upon, or turn them into something else entirely. Therefore, I usually share the slides for my talks. For this, I use SlideShare.
While SlideShare is already useful just for looking at slides, you will actually have to register to get the most out of it. Not only will you be able to upload your own and download other people's slides (if the author allows it) but you can also follow speakers and be notified when they publish new presentations. In other words, it's yet another social network. In fact, since SlideShare is owned by LinkedIn, it is part of a social network that you may already use.
Embedding slides in your LinkedIn profile
Which already brings us to one of the useful features of SlideShare that many people don't seem to be aware of: You can embed your slide decks into your LinkedIn profile. There are 2 ways to do that: You can pick your best slide decks and display them as a gallery, so that people looking at your profile will get an impression of the things you usually speak about.
You can also embed slides into the description of a job. My LinkedIn profile, for example, lists my position as "Speaker Liaison" at TEDxStuttgart. I've embedded a presentation there that we made to explain what TED, TEDx, and TEDxStuttgart are. That slide deck is actually from the TEDxStuttgart SlideShare account, i.e. you can also embed other people's slides into your profile.
Embedding YouTube videos in your SlideShare slide deck
Another interesting feature of SlideShare is that you can embed YouTube videos into your slide deck. It's simple but effective: You simply tell SlideShare to show a certain YouTube video after a certain slide. Handling videos in presentations is still a little awkward and often results in huge files. But if that video you want to show is already available on YouTube, you can simply upload your slides without the video and then add it again via SlideShare.
If you want your slides to be seen, you can of course share them on the usual social networks (Twitter, for example, embeds them and lets you view them right there on Twitter).
To make sure that your slides can be found on SlideShare itself, don't forget to add a description of the talk and to tag it. Add tags for the conference or event you gave the talk at (use their official hashtags) as well as keywords relevant to your topic.
SlideShare also extracts all the text from your slides and adds it as a textual description of the presentation ("Presentation Transcript"). The added bonus is that this text is being searched, so it helps in being able to find your talk.
The kind of more visual slides that I usually produce are at a disadvantage on SlideShare, in that they don't contain a lot of text. So there are fewer keywords in them that could show up when people do a search. In that case, you can add "subtitles" to your slides. I still use an earlier version of Keynote on the Mac which puts the moderator notes under the slides when exported as a PDF. So in SlideShare, you can look at a slide and then read the text that comes with it (example). Newer versions of Keynote seem to put the moderator notes on a separate page when exporting to PDF, unfortunately.
SlideShare apparently also displays speaker notes from ppt, pptx and odp files, but I haven't tested this.
Alternatively, you could add text directly on the slide but hide it behind the graphics. This approach feels a bit sneaky, though, and I'm not sure if SlideShare could see this as spamming (they don't seem to handle it as such currently, but that may change if that approach becomes more widespread).
Speaking of which: Someone from SlideShare left a comment under one of my presentations one day, telling me that they had considered featuring the presentation on the site's front page but considered it too spammy. The problem, apparently, was my practice of linking the photos I was using in the slides to their original URLs (usually on Flickr). You can't see this when you look at the slide, but when you click on it, it takes you to the original photo. It was my attempt to give credit to the photographer, but apparently the amount of external links that this approach creates is frowned upon by SlideShare, even if it was done with the best intentions.
I'm not doing this any more now but instead have a "Credits" slide at the end of a presentation and link to the originals from there.
It's great to have one of your presentations featured on the front page of SlideShare, since it obviously brings a lot of viewers and interest in you and your topic. It has happened to me (twice, with this and this presentation), but I'm afraid I can't really offer any insights on how to achieve this (only the contrary; see above).
Sometimes, it seems to be a question of timing, i.e. a topic is popular and you happen to have a good presentation about it. In the second of the above cases, for example, my presentation was featured as part of an "Event Spotlight" about FOSDEM. It probably also helps if the presentation is visible on social media and gets a lot of shares or retweets; I'm sure SlideShare is monitoring closely which slide decks are being shared on social networks.
I usually try to make my slides available to my audience soon after my talks, sometimes even before I give the talk. The slides may therefore be available in advance, but that doesn't "spoil" people or prevent them from attending the presentation in person. I find that people appreciate it if slides are available soon after a talk, and if you left a good impression, they are happy to share them on social media. So I try to take advantage of that effect and don't care about providing a "sneak preview" (SlideShare does have a feature to mark slide decks as private, but it's only available to paid accounts).
It's more than just sharing
If you only see SlideShare as a means to make your slides available after your presentation, you're missing out on all the other useful features it offers. In fact, the above list is not meant to be exhaustive. Which use cases did I miss? Feel free to add them in the comments. Thanks, and happy (slide) sharing.
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