Finding a good domain name can look impossible – it seems as if all the good ones are taken. However, a new trend for so-called "domain hacks" could mean that there are more possibilities than you think.

A domain hack is a domain name which uses the top-level domain and/or sublevel domains as part of the actual site name. One of the first examples is "http://inter.net" - .net, the top-level domain, is used to complete the word "internet". A more recent (and very successful) example is the social bookmarking site "http://del.icio.us", which uses both a sublevel domain (del) and the .us top-level domain to contribute to spelling out the word "delicious".

There are also domain hacks which don't use the top-level domain as part of the site name, but do use a sublevel domain. For example, "http:// 3.141592653589793238462643383279502884197169399375105820974944592.com", as well as being one of the world's longest domain names, uses a sublevel domain "3" and then the first 64 digits of pi as a second-level domain.

Email hacks can also look very effective. For example, "j@mes.com" uses the @ sign in place of an A in order to spell the name "James". If you are only using your domain for POP3 email, and you have an A somewhere in your name other than the first or last letter, you might want to consider an email hack.

Domain hacks can certainly expand your options for choosing a domain name. However, there are some points to keep in mind if you are considering choosing a domain like this.

- Search engines will "read" the top-level, second-level and sublevel domains as separate words, so even if your complete domain name contains relevant keywords (such as "http://college.camp.us" for a student union site), the search engines will not recognise these keywords if they are partly formed by a subdomain or the top-level domain (so they would only see"college" and "camp", which might bring you untargeted traffic from people looking for college camping trips).

- People wishing to visit your site may forget to put in the dots (so they might type "www.collegecampus.com" instead of your site name). Del.icio.us have got round this problem by registering "www.delicious.com", which resolves to the del.icio.us homepage, but if you are using a domain hack because the name you wanted was already taken, this will presumably not be possible. Also, you may well lose traffic to the owners of the "un-dotted" domain.

- Visitors might also forget where to put the dots, especially if you use subdomains. For example, visitors attempting to find Ma.gnolia.com, another social bookmarking site, might type "mag.nolia.com" or "m.agnolia.com", or a whole variety of other combinations.

- Domain hacks have been criticised for abusing top-level domains by using them in ways for which they were not originally intended. For example, .us is supposed to be used for sites which specifically operate within the US, and other country-code top-level domains could be abused too.

Nevertheless, if you think you can brand your domain hack effectively, and can get round these problems where necessary, the names can be extremely striking and very effective. You could look into some of the less common top-level domains for inspiration, and there are websites available which can do searches for domain hack ideas.

By Natalie Catchpole