Have you ever gained an active member from a post exchange or a posting package? How active are they are on your forum and how many posts do they have?
I have never gained an active member from an exchange or package. However as a packager I am now active on one forum I found while completing a package. 🙂
I (almost) never requested packages or do exchanges so my answer will be no. Personally speaking I don't think it will work too, unless the forum really makes you interested, like in Hissae's story...
The site itself has to be the reason why someone stays, if they are going to stay. No other reason. If there is another reason they join and hang around they will not stay long.
I've only done a few exchanges lately (though a few years ago on other forums I did a decent amount), and to the best of my knowledge, it has only happened once.
I have gained two active members from an exchange, but I think it was because we were already friends before we did the exchange. I come back to their forums as well.
I think with any forum exchange you are going to get a mixed bag. Some will be full of engaged and interested forum members while some will simply give you a bunch of people not really interested in your topic.
This could be a great way to diversify your audience, but it is definitely a gamble.