I'm in the middle of a wild 6-week stint. First Oslo for a week, then home for 4 days, then SMX East and a week in New York City. Tonight, I'm back in Seattle, but only for a few days - our SEOmoz/Distilled London seminar is just a scant 168 hours away. And, of course, on my return, I couldn't help but be compelled to do another set of SEO graphics (first series here) after seeing this great collection of Infographics & Data Visualization Blogs.

These are somewhat disparate, but hopefully valuable. I've provided some descriptions and explanations below each:

This first graph is fairly basic. In low-level competition results - long tail or relatively unpopular queries and sectors - the relative value of basic on-page optimization is very high. That drops down as competition increases because many, many pages and sites will have proper keyword usage and targeting. The engines will instead choose rankings based on popularity and authority metrics, where links play a much larger role. This isn't to say that it isn't still important to get the on-page stuff right; it's just unlikely to give you the boost you'll need to rank well in more competitive arenas.

I've obviously chosen only a few link building tactics to highlight here, but when constructing this graph, I found these to be particularly interesting.

• Manual link building tactics tend to trail off in value (in my experience) as a site becomes better known, more popular and earns a collection of thousands-millions of high quality links. The incremental value added by another tiny directory or article submission site (or other small-site focused tactics like link exchanges or requests) becomes miniscule.
• Linkbait and Viral content is almost always high in value, particularly when you can craft content that helps to bring in links with the right anchor text pointing to the right kinds of places (like badges, widgets and embedded content). However, relatively speaking, the value is highest when the site is brand new and drops gradually with popularity.
• Media + Press links, like Linkbait, are consistently valuable, but the same principles tend to apply. Once you're a behemoth in your field, another link from the Wall Street Journal or the Chicago Tribune won't provide a substantial boost.
• Content licensing (or technology licensing) and partnership-style links are particularly interesting. For new sites, the value tends to be low, simply because you have very little content to license and few big brands are willing to make arrangements with you. As you gain traction, though, this technique climbs in value and, in my experience, provides some of the best ROI for large, dominant sites that can leverage their content warehouses to earn dozens or even hundreds of individual external links to every piece of content they produce through licensing agreements that require a link back to the original.

The panel I spoke on at SMX East about PR Sculpting featured six speakers with six unique perspectives on the topic. While it was tough to find consensus around the minute details of PR Sculpting, the panel mostly agreed that the tactic is primarily valuable for helping sites that have additional pages they want in the main index that simply don't make the cut get in. This handy chart illustrates that principle, showing that, relatively speaking, you're only really getting value out of the practice of PR sculpting (whether you do it with nofollow, careful link selection, link consolidation or something else) when you have pages that languishing in search engine index obscurity (see this recent post for more).

The reason I've made the value low when you have 0-20% of your pages indexed is that this generally corresponds with an overall lack of the required link juice to spread around. You need to get over that barrier before you can start to tackle where to flow it internally to get pages indexed.

Similar to PR sculpting, XML Sitemaps tend to carry more value in certain scenarios (and, interestingly, with certain engines). It's been my experience that Microsoft's Bing engine gives slightly more preferential treatment to pages in XML sitemap files than Google, but at high numbers of URLs, the value is high for both engines (I've not included Yahoo! because I haven't seen consistent results with their treatment of Sitemaps - and because I strongly suspect that 8-10 months from now, we'll be SEO'ing in a two engine world).

p.s. As always, these graphs are based on my personal opinions & experience; please feel free to share your opinions and critiques.