As of lately the search engines have been placing less emphasis on the Meta title tag, Meta description tag, and Meta keyword tag. It has become too easy to manipulate these attributes into misleading searchers to your site. It is not to say that these fields have no impact in regards to SEO and SEM. They title and description tags are great places to have keywords that comprise complete sentences. No longer must you only focus on the search engines (SEO), but now you must make it readable and compelling to searchers (SEM).

The Meta title and Meta description tags are very important aspects to help increase click through rates. If the Meta tags are missing keywords or are unreadable to humans, then they will ultimately fail. Using Google’s AdWords Tool can help target specific keywords that are receiving large volumes of searches with limited competition. Once the keywords are chosen you must manipulate them to flow into sentences that can sell your product or service. The Meta title tag should not exceed 70 characters. The Meta description tag should not exceed 150 characters. Anymore characters will not show up in the search engine results, rendering them useless in terms of SEM. They still are valuable for SEO purposes as the Meta title will still show up on the blue bar on the top left of your website. The Meta keywords tag has no more relevance for SEO purposes. All the emphasis has been moved to links and content. Just remember that the Meta keywords are losing value in the algorithms as we speak.
There has been the question as to whether or not hyphens or underscores are better for search engine optimization. Hyphens are easier for human eyes to read.

When doing a search in Google for the keyword “starting business” with hyphens and underscores the results varied. With the hyphen the two words were treated as separate terms. On the other hand, the underscore came back with a message asking, “Did you mean: starting _business”.

In effect, the underscore is parsed from the query so, whether searching with an underscore or a hyphen, the results are identical. The same holds true in other search engines (MSN.com, Ask.com) as well. Yahoo! still views the variations differently. That can be an advantage if you have low rankings for phrases using hyphens, as you can still have high rankings using underscores.