Before you begin developing your new or updated site, make sure you understand what technologies are going to be used. Making the wrong decision could negatively impact your search engine rankings well into the future.

Flash

Almost all search engines are designed to index websites written in HTML, not flash, so an all-flash website can be disastrous for search engine rankings. If you use a flash intro, make sure you provide a "skip intro" link in HTML. And if you use flash extensively on your site, you may want to provide an HTML alternative for the benefit of search engines, as well as users who don't have flash-enabled browsers.

Frames

Frames make it difficult for search engines to index a site because with frames you usually have multiple pages, perhaps even an entire website, all sharing the same URL. It's URLs that search engines index and link to, so frames make it difficult for them to direct people to your content. There are some instances where frames are useful, but you are generally better off avoiding them if you can.

Regional Domain Names

Some search engines may rank a regional domain name like ".ca" lower than if it was ".com" domain. However, it is generally believed Google is NOT one of these search engines. In fact if you have a ".ca" domain then you should get a higher ranking at Google's Canadian branded version, google.ca

Splash Pages

Splash pages can hurt your search engine rankings because they usually have little or no content for the search engines to index. This means that the primary URL for your website will get a low ranking. This is especially bad because the other websites that link to you will probably be linking to that poorly-ranked splash page, so you gain little benefit in the rankings from those links.

Dynamic vs static

Search engines generally don't penalise dynamic websites, but they will try to avoid complex database-driven sites. The reason is that the number of pages in such a site could be virtually unlimited, putting the search engine at risk of wasting its own resources, and of putting too much strain on the webserver by requesting pages too quickly and possibly crashing the website. A good rule is that if the URL contains a question mark, then you can question whether a search engine will ever see it.