To link or not to link?

An attorney I know received an email from another law office inviting her to write a blog for the law firm to post on its website. Then each firm would link to the other's website.

What's going on?
The law office making the request is attempting to increase its page rank in organic (unpaid) search results. This is an established Search Engine Optimization technique. Google and other search engines place a site higher in the results if there are a lot of "high quality" links into the site. By "high quality" they mean links from related sites rather than links from your mother's Facebook page or random directories that no one ever uses.

So, should you do this?
Link building is always a good idea IF the links are an integral part of your content, provide value to your customers, and may be good sources of referrals.

Guest blogging is also a good idea. Having your blog posted on someone else's website gives you more visibility and credibility, not to mention links back to your site.

Offering to trade blogs with other sites is a great way to get your site updated more often -- always a plus with the search engines -- and improve your visibility.

So the answer is: Yes, link.