I've noticed a nasty habit on Google+, and I think it's time to speak up about it.
If you comment on someone's post with a clever way to link to your own post, congratulations - you're an opportunist, and many marketers probably think you're brilliant. But you're kind of being a jerk. Here's why:
It's About Intentions
The comment thread on someone's post is intended to allow for conversation around that post, which can include debate, discussion, and yes, sometimes off-topic utterances. The more readers the post has, the more robust that conversation can be. When you link to your own post in a comment thread, you're redirecting readers who would otherwise have contributed to the original comment thread (which would make that conversation more awesome and diverse). When that redirection is your goal, you're being a jerk.
Join The Conversation Instead
The original poster would almost always prefer you keep the conversation in his or her thread, as long as it's relevant. Why? To keep the conversation flowing. To keep things interesting, engaging, and relevant.
There is a ridiculously high character limit on comments. That means you have a chance to add as much of your opinion as you want on the original poster's real estate. Some of the best comment threads I've ever read had lots of long-winded replies!
Contribute instead of trying to hijack, because karma is super real on the social web.
Sometimes it does make sense to respond to a post with a post of your own.
If a comment thread is getting very long or convoluted, and you want to bring up a point that is related to the main conversation but would honestly make more sense as a post on your own profile, share the original post and add your commentary as an introduction. And if you feel the need to link to your new post in the original post's comments, don't link to it without also contributing to the original comment thread in a way that's sincere.
Sometimes, you wrote a post 6 months ago that makes the same points being expressed in a new post you've stumbled upon. If you want to link back to your old post at the end of your insightful comment on the new post, that's not being a jerk. That's offering supplemental reading.
Thread hijacking is one of those things - we just know it when we see it, and we know it's not cool.
We should be elevating each other, not trying to hoard followers and engagement.
In summation: be excellent to each other.