If I understand you correct, you're saying that every since your traffic has been up you are getting a ton of people spamming your blog and you're wondering if there is anything to gain there... If it's clearly spam, weird email addresses and stupid comments like "great point, you really made me think"... without any reference to the post.... then no. That is all pretty useless. I'd install Akismet if you haven't already. That pretty much handles it. I'd also set things so that a comment doesn't appear without being approved with even one link in it. If they continue, add a capchta code for a while. That will kill it. Then you can turn it off after a while.

If they are legit comments then there is a lot you can do. Let me know if thats the case.

I haven't personally found the spam to e associated with ads. It's just something that hits every blog I have sooner or later until I take the steps mentioned above. It's a real pain and it's mostly all just link spam from bots controlled overseas.

Let me know if I misunderstood.

What you are describing is a pretty common thing and I doubt it has anything to do with FB ads. Though I could be wrong. Probably just a coincidence. I don't have people subscribe to my blogs in that way, with the exception of my membership sites. Are you doing something that requires your readers to subscribe? Such as leaving a comment? If not then I'd say those are probably all spam. I've had sites with thousands of spam accounts. You can usually tell at a glance. Adding a captcha ode plugin usually stops it. Then after a while I just remove the captcha code until it starts again.

I actually don't know how it works but I assume your blog gets adding to a bot's list once you hit a certain Alexa ranking or something. That may be what happened when you started getting a boost in traffic. I assume though that when the bot fails enough times you get removed. Just a guess though. i have no idea what is really happening there.

But long story short, I don't require anyone to register for my site with the exception of membership sites which use wishlist as apposed to the standard wordpress subscription forms. You could then turn off the "allow new users" option if you wanted. If you don't have some user based functionality to your site I see no reason for it. And a mailing list through Aweber is infinitely easier and more valuable for both you and the subscriber.

Hope that helps.

To my knowledge there is no way for Google to know how many subscribed readers you have. There are ways for them to access RSS subscriber totals though and that does matter (as far as I am aware). So getting people to subscribe to your blog's RSS feed is something you want to encourage. But if you don't require people to become users in order to comment I can see no reason to allow people to subscribe. It's usually only something you use when you are allowing multiple authors, or limiting access to content in some way. I have zero users aside from admin to most of my sites and they have all done very well in the serps. I think it's RSS subscribers that you are thinking of in this matter.

Sorry, I think we still have some confusion here. That's not exactly what I was trying to say. Yes, you can require people to register to leave comments but I would definitely not do that. That will just insure that no legit person ever leaves a comment.

The reason wordpress allows people to register is because blogs were designed with things like multiple authors and password protected content in mind. One function that some people use to attempt to protect themselves from spam is to require commenters to register an account (subscribe as you and I are referring to). But all thats happened is that spammers send bots out to create accounts on mass and then leave comments to get around the "require people to register as a user in order to leave a comment" setting. The spammers do this on mass, regardless of whether or not you require commenters to be subscribers. If you require people to subscribe all you will do is make it too much work to leave a comment and no one will. Worst still, you will have a bunch of subscribers you never contact because emailing blog subscribers is infinitely less effective that emailing mailing list subscribers.

In short, don't worry about this. Allow anyone to comment and install the Akismet plugin. If it continues, add a captcha plugin and set things so that all comments must be approved. After a while you will be able to set them to auto approve if you want and turn off the captcha. The problem tends to go in waves.

I'd temporarily turn off the ability to register for your blog. You really don't need it unless you have a membership site. you can turn it back on after the comments stop