6 different users used the WordPress “like” button on this post, 3 from the same IP in Seattle, 3 from the same IP in Germany. All the user names are spammy.
But I don’t get what the spam/scam is. They don’t get links back as far as I can tell.
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Richard WM Jones 
Beta testing the system ?
Or maybe they just do that to appear as legit users that do recommend various blog and not only the one they want to promote ?
Commonly on wordpress, once you allow a single comment from a user, they can comment again without approval. Watch for a link farm on another post in the future. Possibly right after another semi-popular blog post.
I’m watching all new comments, even approved ones.
I agree the controls on WP aren’t very scalable. If I had more than a handful of comments per day it would be hard to keep track of it.
They’re making the post more popular, so when they post a spammy comment to it in the future, it will be rated higher.
Or, they hit “like” at the same time AS posting a spammy comment, but the filter caught the comment.