Freelance contractor network Elance released its August edition of the "Elance Work Index" which ranks the top 100 skills in today's online labor market.

The data is derived from more than 100,000 jobs posted on Elance in the past few months and is a good market indicator for online work tracking 9what companies - or individuals - are hiring for).

What this month’s index shows is a continued need for IT and marketing expertise with graphic design, open source technologies, and online marketing skills (once again) topping the charts.

Notable trends from this month’s Index include:

- Graphic Design (#1) has regained the top spot in the Index trumping PHP (#2) which had held the pole position the past four consecutive months.

- Technology hiring trends continue to reaffirm the open-source movement with PHP (#2), MySQL (#3), and Joomla! (#8) firmly entrenched in the Top 10.

- Demand for cost-effective customer acquisition is demonstrated by Internet Marketing (#7) moving up five spots and bolstered by the Top 25 placement of Search Engine Optimization (#21), Lead Generation (#22), and Sales (#23).

- Demand for Twitter (#71) expertise dropped 25 slots, with Facebook (#63) and Social Networking (#45) also falling this month.

- Google Website Optimizer (#31) made a huge 28 spot leap, and Google Analytics (#93) and Google AdSense (#68) both debuting in the Index for their first time.