I am writing this to clue you people in who deal in good faith when exchanging links with other sites. Since there is such a frenzy among us to establish backlinks for page rank and search engine result pages, you have to stay on your toes all the time when assessing link partners. The simple truth is many sites are set up to snare the unwary, and generate 1-way incoming links for them which are more valuable than 2-way recipricols. These sites have no intention of dealing fairly with you, or posting your link in any place googlebot could find it to give you the credit for it. Its all 1-way with the scammers, but take heart, if you know what to look for these sites won't be taking advantage of you.
2. The site should have a links, or resouces directory on the links page, and so should yours. The reason is obvious. Googlebot will only follow 2 pages deep off the home page normally, and disregard everything else. With the directory, all the link pages stay within the the 2 page deep limit. Example home/linkdirectory/pg1 The linkdirectory is on the links page, and this page is 1 page deep off the home page containing all the different catagorys. When you pick a catagory its resulting page is only 2 pages deep off the home page pg1 which assures it will get indexed and crawled, and if your link is there you will get credit. Another excellent reason for having a catagorized directory is that many times your partners link will not be directly associated with the business you are in and therefore may be seen as having no "relevancy" to your site by google. But if the link is in a catagory that is "relevant" to it, its good, and you will get credit for it.
3. Avoid sites that simply have an endless string of link pages. Example: links pg1,pg2,pg3,pg4,etc.. For the reasons stated above googlebot only follow 2 pages deep, so pg3,pg4, and all others following them will be ignored. Sites like this are link farms by definition, and will eventually incur the wrath of google, which frowns on link farms.
4. Do not assume the site you are considering trading with is good simply because it is listed in the directory of a link exchange service. It has been my experience that link exchanges do not critique their members navigation structures. Knowing this, these scam sites are littered throughout the link exchanges hoping to snare the unwary. The link exchange may ask them for the page they post your link on, but do not check it by googles navigation rules. Scammers will post your link on a page that is not rigged to their sites normal navigation, or buried to deep, or to far away from the home page to be indexed. It is your job to determine the intent of your partner, to either display your link in the open on a page that will get you the credit when it is crawled, or if they intend to bury you deep and scam you for a 1-way incoming, placing you on a page they know will never be crawled.
5. Be wary of sites that link to "bad neigborhoods" ie, porn, hacking, warez and the like. Linking to them is dangerous. If google decides to drop the hammer on them, you could get penalized as well through your association.. Only google "knows" what a bad neighborhood is, but it is basically defined as sites that use illegal, or frowned upon spamming methods. These "types" of sites are notorious for this kind of behaviour, spam, redirects, drive by downloads, cloaks, etc..
6. As a rule, if you cannot follow a sites navigation to find the recipricol links, either can google, so aviod them.
7. Limit the amount of links on your catagory pages to a safe limit of 60 if you can. Pages with to many links get ignored by googlbot as well. There is a lot of debate on the number of links on a page you can actually get away with, some say 80, some say 100, some say more, but 60 is safe. If you get to many links for a certain catagory, think about adding another complimentary catagory where you could add some to relieve the pressure, but try to avoid adding a pg2. This page will be 3 pages deep off the home page, and will probably be ignored by googlebot.
Now, I know this set of guidelines will eliminate an awful lot of sites, but these sites either through ignorance, or intent, are not structured to give you the credit you are seeking for your reciprocol link. If its a case of ignorance, a simple heads up with an email can work wonders. I have many friends who were trying to establish reciprocols and getting nowhere, who were grateful for the advise, made changes, and got partners. Not everyone is up on link protocol, so I would advise giving the benefit of the doubt at first. Remember that potential partners will be critiqing your site for its navigation as well, so practice what you preach.
If, on the other hand its intent, i'll bet you never get a reply, but thats an answer in itself, isn't it? Remember that every time you link up, you are "sharing" your page rank, so it is well worth your while to make sure the courtesy is returned.