Lots of people are building web-apps nowadays. There are a lot of things to pay attention to: User-interface, scalability, functionality, and community among them. But one thing that a lot of people overlook is good old search engine optimization.

Spider

Web 2.0 generates a lot of content. In fact one of the memes of Web 2.0 is “Let the users create your content.” It is my philosophy that making this content search engine indexable is in your best interests.

Opening up your content to search engines is not only extremely beneficial to the online populous (and your existing users), it also attracts new users that you would never have been able to reach.

Let’s look at some simple techniques that you can easily integrate into your web application.

Note: Not all of these are applicable to all web applications. In fact some web-apps are not conducive to SEO at all. For example, Mint (an online money-management tool) would be very hard to open up to search engines because its “content” is sensitive financial information.

Public Content

First and foremost, open up your content. Your site can’t be indexed if all of your information is encapsulated in a walled garden. Opening up your content will allow you to benefit from the wealth of information that your users create. You will gain search hits from what is known as the long-tail of Internet search.

Try browsing your application as a guest. Is your site usable if you are not logged in? If the answer is no, try rethinking your structure to make your content accessible to logged-out users.

Good Titles

One of the easiest and most important things that you can do to improve your rankings is making sure your pages have good titles that match your content.

Search engines highly value keywords in the title so think about what title will accurately and helpfully describe the content of your page.

Rewrite URLs

Using Apache’s mod_rewrite in your web application can be a useful tool. Not only do search engines highly value keywords in URLs but it also gives your links better anchor-text.

Plus, you will get your site more thoroughly indexed using mod_rewrite. Spiders oftentimes ignore URLs with long variable strings. A search engine may end up only indexing a few articles from a site because it doesn’t know which variables are relevant.

Several sites use mod_rewrite to achieve fantastic search engine results. Among them are Digg and Wikipedia which have become ubiquitous in Google Search Engine Results Pages (SERPS).

Semantics

Be sure to properly markup your pages to highlight important information. Use of the header tags (<h1> through<h6>) are helpful because they let search engines know what is important and what isn’t.But don’t overdue it. For example, it would be an unwise decision to do a find and replace as you serve pages to surround specific keywords with <h1> tags as this likely be penalized as spam by search engines.

Well-Anchored Links

Similarly, look through your application and see what kind of anchor text you are using. Try to replace any “Click Here” or “Read” links with more descriptive anchor text (like the subject or title of the linked-page). Search engines love well-anchored links and will reward the effort.

Link Baiting

Finally, try to think of ways to give your users incentive to link back to your pages. Social news sites are the champions of this. They give you something to gloat to your users about. If a site is dugg to the homepage they oftentimes link to the Digg article (or submit one and link to it in hopes that it will get to the frontpage and bring in traffic).

Link-baiting can be anything from encouraging users to link back to your site (eg. YouTube gives you embed links for their videos) to running a contest. It’s getting your users do your link-building in addition to having them create your content.

Conclusion

Using these techniques to search engine optimize your Web 2.0 application should greatly increase your traffic, your signups, and your revenue. Let us know any other tips you’ve run across in the comments.