This week, four internet and web service stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

Commtouch Software Ltd (CTCH) is bettering its rating of C (“hold”) from last week to a B (“buy”) this week. Commtouch Software provides messaging, antivirus, and Web security solutions to OEM customers, enterprises, and service providers primarily in Israel, North America, Europe, and Asia. In Portfolio Grader’s specific subcategory of Sales Growth, CTCH also gets an A. For more information, get Portfolio Grader’s complete analysis of CTCH stock.

This week, OpenTable, Inc.’s (OPEN) ratings are up from a C last week to a B. OpenTable provides free, real-time online restaurant reservations for diners through an online booking service. For more information, get Portfolio Grader’s complete analysis of OPEN stock.

Internap Corporation (INAP) shows solid improvement this week. The company’s rating rises from a C to a B. Internap Network Services provides a broad range of scalable information technology infrastructure services for enterprises. For more information, get Portfolio Grader’s complete analysis of INAP stock.

Bitauto Holdings Ltd. Sponsored ADR (BITA) is making headway this week, with the company’s rating improving to an A (“strong buy”) from a B (“buy”) last week. Bitauto provides Internet content and marketing services for the automotive industry, primarily in the People’’s Republic of China. For more information, get Portfolio Grader’s complete analysis of BITA 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.