You need to distinguish between what Tumblr is and what most people use Tumblr for.
Firstly, it's just a (lightweight) blogging platform with a (very lightweight) social networking layer. As a blog site, it has a few advantages over Wordpress and Blogger and the like:
- Very quick to sign up, and has robust multi-site support; you can add endless Tumblr sites all under the same account (I'm up to nine now on mine!).
- Very easy to post to, particularly good for media content like sound, picture sets, and video clips.
- Doesn't nickle-and-dime you for charges for things like using a custom domain name.
- Has a good selection of free themes and some outstanding low-cost commercial themes.
The social networking layer comprises of the following bits:
- You can build a list of people you follow, and the "dashboard" view shows you all their posts in chronological order -- a bit like an aggregated RSS feed.
- You can "heart" posts you like, letting the person know you liked it.
- You can "reblog" content, taking someone's post and putting it on your own blog, with some annotation you can add. Tumblr keeps a citation chain for this so people know it's not your content. This is how, say, wacky pictures get passed around the site.
- The dashboard view (which serves up several billion hits a month -- seriously) has a little boxout called the "radar" which cycles between half a dozen of the current popular posts across the entire site. Get something in there and millions of people will see it.
Now, Mimi is quite right that an
awful lot of people are just using it for wacky pictures, pop culture ephemera, and quite nice photographs they've seen on Flickr and are now posting without any sort of atttribution to the photographer. Lightweight stuff, in other words. I hate most of those guys! But of course I don't read their stuff so I also don't care much. If you look, there's plenty of people using it as a straight blogging platform (like me!). And there's all sorts of weirdo sites too.
http://dailybez.tumblr.com/ and
http://whatsonstevebuscemisstoop.tumblr.com/ and
http://eatingoffthepeoplesprincess.tumblr.com/ all spring to mind, and this sort of slightly deranged micro-content can find a receptive audience.
What your boss is getting at, Nirejhenge, is that scans of terrible 70s and 80s B-movie VHS covers are the sorts of things that would get popular on Tumblr -- people like that sort of thing. A snarky joke at the bottom of each one would be good too.
It's very different from flickr, because you'd want to post one a day or something (tumblr has a queue, so you just bang loads of posts in in one sitting and then tell it to put one live at a certain time each day). This is a much better way to build readers than a shitload of pics on flickr that hardly anyone will look beyond the first page of.
You've nothing to lose from trying it -- you could probably sign up, choose a theme, and get a post up in less than ten minutes.