I've been working on a directory of my own I was going to publish soon... now I'm not so sure.

If I do, just to be safe I doubt I'll have the word 'reciprocate' anywhere in my text.

Historically, I've never been fond of reciprocal as a requirement, but do see it's value in some situations. I can also see Google's view that in some cases the directory of reciprocal links may be like a distant cousin of link farming, except with categories.

Perhaps to side step that stigma, and to have a legitimate directory that won't be seen as such, would be to make sure each category went to a separate page of links, and that page of links was totally dedicated to that category / topic. Know what I mean -- keep oranges with oranges and apples with apples. Most already do that, perhaps the danger is with having apples and oranges linking out from the same page. Though, does Google see the relevancy of a site as a whole, or look at the theme of each page individually? I'm not positive about the answer to that, but I would think the latter because there are large sites that cover a range of topics with outgoing links from those pages. To do the same and call it a 'directory' -- may dodge the accusation of 'spamming', or reciprocal links for the sake of PR.

As for reciprocating, perhaps it's done best under the table, the old fashioned way. That is, a polite email requesting a reciprocal link first. Just a suggestion...