On both #Twitter and #Tumblr, I get followed at least daily by accounts with generated-looking names, conventionally-attractive female profile pics, and (on tumblr) no posts or (on twitter) a few posts that are just pictures of women (sometimes completely different women).

What is up with these?? What is the scam? I keep waiting for the other shoe to drop, but nothing so far...

(On Twitter I remove them as followers on my main account, and let them accumulate on a backup account. On Tumblr I ignore them. Nothing has ever happened.)