When you search Google on a mobile device, any website that is not mobile-friendly will be harder to find from today.

A/B testing is the practice of changing two variants in online advertising in an attempt to maximise conversions and gain more sales. It's something companies do regularly. There's a right way and a wrong way to perform an A/B test, though. If you aren't maximising your conversions, you're doing it wrong.

Blogger and developer Matt Gemmell has gazed into the dark side of of search engine optimisation (SEO), and while he understands the value of having your personal site, your blog or your company's website rank well in search results, he's not willing to sell his soul to do it. Instead, he's written a simple guide to SEO for the less cut-throat.

Everyone and their dog has an opinion on how to perform "search-engine optimisation" (SEO) and make your online business more visible in major search engines; how do you distinguish the potentially useful tactics from the snake oil salesmen? The simple answer: put your energy into building a quality site rather than worrying about the search impact of what you have done.

Although Google's indexing methodology is now much more sophisticated than merely tracking link referrals, creating inbound links to a site remains a popular tactic -- and one that's increasingly exploited by unscrupulous site promoters who use hacking techniques potentially add invisible links to their sites onto other legitimate pages. Not only does that give bogus operators higher rankings more traffic, it can also affect your own site's visibility, since Google and other spiders often rank sites lower if they appear to be designed to game search rankings.Blogger Patrick Altoft suggests a neat trick to track possible intrusions of this kind on your own site: using Google Alerts to track the addition of spurious terms to your site. This isn't a perfect approach, and you'll need to deal with any security vulnerabilities that make such code injection possible in the first place, but it's a neat way to detect obvious attacks.How to use Google Alerts to find out if your site gets hacked

HubSpot's Website Grader is a web-based tool which analyses and scores your website against a number of criteria, and provides you with a report card flagging areas you may wish to improve. By filling out a web form which asks for your URL, keywords related to your blog and optionally any websites you compete against, it generates a report on your site. You need to supply an email address as it mails the link to you.The score it generates grades your website against a number of things including website traffic, search engine optimisation, social
popularity (via social bookmarking and sites like Digg) and a wide range of other factors. It also provides some very basic
advice on how you can improve your website's  performance.One thing which tickled me is that it rated Lifehacker's readability as "advanced/doctoral" level. I had no idea we were so rarified! I'd better duck back to uni and get that PhD. :)What's Your Website Score?

Two years ago, we introduced website owners to the art of SEO with some basic tips and tricks.