Hi I have 10 travel websites. Should I do cross link all of them at the footer in order to increase PageRank and send users to each websites. I will use domain-name.com to be text link,such as, bostonhotels.com - parishotels.com - newyorkhotels.com - bangkokhotels.com Many Thanks
Sure you should definitely do this....if you want Google to ban all of your websites! That is a spammy technique and a deliberate attempt to artificially improve your search engine rankings. It is usually fine to have a few cross links, but mass cross linking your network of websites together is not a good idea. If you want to do this for your visitors, instead use a drop down menu with the different cities. Then redirect the visitor when that drop down menu changes.
Cross linking sites are 100% fine by Google as long as they are related. Just try to make the links look natural.
In the mighty words of Googles Matt Cutts. Do what is good for your visitors. Forget about the SEO. If it makes sense to your visitors then it is a good thing. If you think it will boost your ranking somehow, you could be right, and you could be wrong.