Biblical interpretation is a church practice with an ancient history, and historical commentaries include some of the most theologically or historically significant commentaries that have been produced. While you should follow current developments in scholarship, do not overlook some of the historicaly valuable voices of our tradition.
While you can appreciate them for their theological genius, be sensitive to the occasion and context for their writing. Also consider that these commentaries may speak more to the mind of the author than to the Scriptural texts themselves.
Different commentaries (whether a series or an individual volume) often represent different perspectives; some will be broad, some will have a very specialized focus. Read commentaries to get a variety of theological, scholarly, and cultural perspectives. While you might start to favor one commentary over others, be open to encountering other voices.
Links to web-based resources are not a guarantee of the integrity or accuracy of that website's contents or an endorsement of other services available through that website.
If you can, identify the source for the material you find online. Who is the author or editor? What are this person's credentials? Likewise, what are the credentials of the website's publisher? Does the website have a stated mission or goal, so that you can better understand the context for these resources?
Many of these websites are often the work of well-meaning volunteers but may have limited quality control. If your scholarship relies on use of some of the classic commentaries, you should confirm your citation against a printed edition.