This week, the ratings of 10 internet and web service stocks on Portfolio Grader are down. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Youku Tudou, Inc. Sponsored ADR Class A’s (YOKU) rating falls this week to an F (“strong sell”), down from last week’s D (“sell”). Youku Tudou is an Internet television company. Shares of the stock are being traded at a very rapid pace, up 434.8% from the week prior. For more information, get Portfolio Grader’s complete analysis of YOKU stock.

The rating of Marchex, Inc. Class B (MCHX) slips from a D to an F. Marchex offers call-based advertising and related services, pay-per-click advertising and related services and proprietary traffic sources. The stock receives F’s in Earnings Growth, Earnings Momentum and Earnings Surprise. Equity and Cash Flow also get F’s. To get an in-depth look at MCHX, get Portfolio Grader’s complete analysis of MCHX stock.

Unwired Planet, Inc.’s (UPIP) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Unwired Planet develops patents that allow mobile devices to connect to the Internet. The stock gets F’s in Earnings Revisions and Equity. For more information, get Portfolio Grader’s complete analysis of UPIP stock.

The rating of ChinaCache International Holdings Ltd. Sponsored ADR (CCIH) declines this week from a C to a D. ChinaCache International provides a portfolio of services and solutions to businesses, government agencies and other enterprises to enhance the reliability and scalability of their online services and applications and improve end-user experience. To get an in-depth look at CCIH, get Portfolio Grader’s complete analysis of CCIH stock.

E2open, Inc. (EOPN) experiences a ratings drop this week, going from last week’s D to an F. E2open develops and deploys enterprise software cloud solutions for businesses. The stock gets F’s in Equity and Cash Flow. For more information, get Portfolio Grader’s complete analysis of EOPN stock.

Slipping from a D to an F rating, iPass (IPAS) takes a hit this week. iPass offers enterprise mobility services on a global basis by providing services that simply, smartly and openly facilitate network access from mobile devices while providing the enterprise with visibility and control over their mobile ecosystem. The stock receives F’s in Earnings Revisions, Equity, Cash Flow and Sales Growth. To get an in-depth look at IPAS, get Portfolio Grader’s complete analysis of IPAS stock.

This week, Velti’s (VELT) rating worsens to an F from the company’s D rating a week ago. Velti is a global provider of mobile marketing and advertising solutions. The stock gets F’s in Earnings Growth and Earnings Momentum. For more information, get Portfolio Grader’s complete analysis of VELT stock.

Travelzoo’s (TZOO) rating weakens this week, dropping to an F versus last week’s D. Travelzoo is an Internet media company that publishes travel and entertainment deals from travel and entertainment companies, and local businesses in North America, Europe, and the Asia Pacific. The stock gets F’s in Earnings Growth, Earnings Revisions and Sales Growth. To get an in-depth look at TZOO, get Portfolio Grader’s complete analysis of TZOO stock.

This is a rough week for Homeaway, Inc. (AWAY). The company’s rating falls to F from the previous week’s D. HomeAway operates an online marketplace for the vacation rental industry worldwide, and offers homes, condominiums, villas, and cabins to the public on a nightly, weekly, or monthly basis. The stock gets F’s in Earnings Growth and Margin Growth. The stock has a trailing PE Ratio of 418.70. For more information, get Portfolio Grader’s complete analysis of AWAY stock.

CoStar Group, Inc. (CSGP) earns a D this week, falling from last week’s grade of C. CoStar provides information and analytic services to the commercial real estate industry in the United States, the United Kingdom, and France. The stock also gets an F in Earnings Momentum. The stock currently has a trailing PE Ratio of 215.40. To get an in-depth look at CSGP, get Portfolio Grader’s complete analysis of CSGP stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.