I once got a letter from LinkPartners offering listing there. I accepted because I did not find anything automatic in it. They are somehow affiliated with LinksManager and that may be another thing but you do not have to use LinksManager. And I don't.
LinkPartners just send you a letter saying that this or that site wants to swap links. But it is your choice, you do not have to accept the suggestion. Most of the time I have not accepted either because the sites had nothing to do with my themes or I did not like them. But I have got a pair of good links too. And it may be easier in the future, because there is now a new feature - you can choose from what kind of sites you accept suggestions. But they are just suggrestions still.
If anyone knows any dangers in using LinkPartners this way (wíthout using LinksManager) I too would like to know.