To get better results how long a link should keep? I saw lot of people by links for a just a month or two. Keeping a link for a shorter time will not gain any advantage. I appreciate your ideas.
Heres the procedure: People buy link for many purpose. Some buy for PR, Some buy for Traffic. For example, if a person wants to buy for traffic, I think one month will be enough because if his site is something special, the visitors will keep coming. If he buys for PR, it can still be useful as it will be counted as an backlink. Hope it helps
If you're talking about ranking, they should stay indefinitaly. Some people buy links for only a few months to get their site spidered as well, but I think the main reason why people stop after a few months is that they don't see any real benefit yet. That is mostly because it just takes time for SE's to find the links, index them and rank accordingly. MSN is supersuper fast, Google is fast and Yahoo is just plain slow in recognizing the backlinks and giving credit to them.
link on a high PR site can stay for a short time if you need to be listed/spidered. For extended PR purposes I think you should leave it there for quite a bit longer.
Google gives more weight to older links. If you want long term rankings you need to build long term links. Obviously if the link is flagged as a paid link it won't help much in the long or short term.
also you better be aware who are you paying It is better to choose a friendly link ...... It is easy to check them form G , Y , M In one month :: you shall have your site indexed In three months :: you shall have at least one time PR update
I suggest you to keep link well links. As long as a partner keeps your site as a good link or a helpful link I think you shall all keep their links with no cheat. There are many places to gain links for free. If you pay for a link then you shall also consider of traffic result from the link. Conditions for not using links 1. all search engines are down. 2. your site is down. 3. people need your site very much " your site are very popular already "
But if you are full of old links, isn't google also thinking you have an old/expired website? just try to buy 10 backlinks for a website, and not buy any more links..you will get down in serpos...why?!