Can SPA (single page architecture) websites be SEO friendly?

[Robo342]

What is the latest consensus on SPA web design architecture and SEO friendliness?
By SPA, I mean rather than each page having its own unique URL, instead each page would have an anchor added to a single URL. For example:

• Before SPA: website.com/home/green.html
• After SPA: website.com/home.html#green (rendering a new page using AJAX)

It would seem that Google may have trouble differentiating pages with unique anchors vs unique URLs, but have they adapted to this style of architecture yet? Are there any best practices around this?

Some developers are moving to SPA as the state of the art in architecture (e.g., see this thread: http://www.linkedin.com/groups/Google-crawling-websites-built-using-121615.S.219120193), and yet there may be a conflict between SPA and SEO.

Any thoughts or black and white answers?

Thanks.

[AlanBleiweiss]

There's no single answer here, however the general consensus is that it really depends on several factors:

• Most pages can only truly be optimized for a couple high value phrases. So if you have too many phrases you want that single page to rank for, that's a tall order.
• If you go too divergent in a single page's topical focus, that makes more of a mess due to topical dilution - weakening the primary phrase focus for that page.
• If you force users to scroll forever (not just due to HTML5 / fluid design) that can be frustrating for readers on several levels.  That's made worse by the fact that most sites that use a one-page design tend to be one-hit-wonder magic-product sales pitch type sites, and thus reputation is an issue due to association with those for some visitors.
• That's just a few of the reasons one-page design is not highly recommended, both from an SEO and a User Experience perspective.
• As far as Google being able to figure out hashtag referenced content - just like every other thing their algorithms attempt to figure out, my recommendations to clients always state "don't rely on that - algorithms are inherently flawed to one degree or another - so figuring out JavaScript, AJAX, Flash - it's a crap-shoot.  Google needs multiple signals to help it figure out topical focus.  With only one URL, you lose the page TItle, URL, H1 and other related signals that only work best when there's one of each of those for separate main topics.  Sure, with HTML5 you are "allowed" to have multiple H1 tags on a page. Yet I've seen that confuse Google's algorithms.  It's just not wise to tempt the "formulaic attempt" process.