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

Commtouch Software Ltd’s (CTCH) grade is moving up to a B (“buy”) this week from last week’s C (“hold”). 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.

OpenTable, Inc. (OPEN) gets a higher grade this week, advancing 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) earns a B this week, jumping up from last week’s grade of C. 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 progressing from last week’s rating of B (“buy”) as the company improves to an A (“strong buy”) this week. Bitauto provides Internet content and marketing services for the automotive industry, primarily in the People’’s Republic of China. Shares of the stock have been changing hands at an unusually rapid pace, twice the rate of the week prior. 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.