Most of my blogs don't get deleted. Here's what I do.

1. I create only 1 blog per user name/email address.

2 Immediately post something that looks legit like, "welcome to my blog ...." about 50 words. Or post a small article 200 - 300 words. I don't worry about the dupe content penalty, I only use them for backlinks.

3. Post an RSS feed and 4 or 5 sentence blurb once a week.

It has worked so far on the free blog sites. I have about 150 sites so far.