In fact it sounds almost too good to be true and, silly old cynic that I am, I find myself wondering why on earth anyone in their right mind would want to go to the trouble and expense of running a web server so that I could hand out free 50Mb chunks of space to anyone who happened along. What's in it for them? would be the first question I would ask myself, and of course we all know that there must be something in it for them.
To start with they want to attract advertisers - and they plan to do that by aggregating the hits on all the sites hosted on their servers. They can do that because you agree to it when you sign up. Once they have plenty of free-hosted sites they'll attract advertisers, and then there will be advertising on all the site's pages. No problems for you, because you have an ad-free guarantee.
You also have an unlimited bandwidth promise, but do not count on this, because it will not be the case. Try using big chunks of bandwidth and see what happens - you'll soon be off the server, no doubt about it.
Don't try using your space for any kind of file storage - If you have no hits and no site edits for 30 days you'll lose your space.
As long as you understand all of that it's a good deal - as long as the company lasts you can't really lose anything.