You read it right
Once you get to a certain number of posts and/or karma, we're thinking of rewarding you by making your homepage link do-follow. Links from posts to your profile are already dofollow, so those pages are getting juice.
Of course it's going to be spammable (what isn't?) but we don't mind, us mods will police things a bit if people really start abusing things.
People putting out loads of short posts can be defeated by giving those posts a thumbs down (click the heart icon to rank posts). Individuals trying to remove others karma shouldn't have a big impact if everyone votes; we'll see how that part works. As for some kind of massive abuse, bear in mind that it'll take mods about 2 minutes to put in a coupla SQL queries and undo spamming, and much more than that to code things.
Right! So - what kind of post and karma levels do you think we should do it at?