How can unaffilitated individuals sign up for Web of Knowledge / Science? I am conducting a meta-analysis of literature and several individuals recommended that I use Web of Knowledge, instead of just Google Scholar. The specific part of it I would need would be Web of Science.

I am not affiliated with any institution; I'm just an independent researcher. I don't see any option to sign up?

On the sign-in page it says:


  NOT REGISTERED?
  
  Take advantage of many great features when you register.

Access Web of Science from outside your institution using **roaming** capabilities
Set up citation alerts whereby you are notified by email when an article on your Alerts list has been cited

  
  Learn more about the benefits of registering for an account


However, when I follow the "Learn more" link I don't see any option to sign up and there are no further mentions of this "roaming" option.
First, as @Anyon suggested in a comment, email their contact form to see if they have a practical solution for you.

If that doesn't help, then I don't have a definitive solution to your very real problem, but I can point you to some possibilities that come from the fantastic article, "You’re a Researcher Without a Library: What Do You Do?":


Go to your closest local university library. Their onsite wifi network might give you the online access you need. (I suspect from your related question [Meta-analysis using Google Scholar - are all years equally complete? that you might want to scrape the site, so you might need wifi guest access within the building to do that.)
If there is no nearby university library, try the largest nearby local library and see if they have access.
Try to get some sort of research affiliate status with a university, perhaps by finding an academic coauthor.


Sorry, but I cannot recommend the options in that article of questionable legality.

Best wishes; I feel your pain and hope you work something out! Please update your question with an epilogue if you do find a solution; I'm sure it will help a lot of people in your situation!