The government has introduced a new website ostensibly to match employers with jobseekers.  Employers can register and post vacancies, while those looking for jobs can register and find the appropriate vacancies.  Sounds sensible.  But a number of problems have already arisen.  There is no human check on what vacancies are being posted, and Channel 4 News this week showed how a group of hackers (although they didn't need to actually hack the site) were able to register as employers, post phony vacancies and then harvest the personal data of those who applied.  Then there's the fact that all the DWP guidance says that it's not compulsory for jobseekers to register, but many people on JSA are being told that it is, and threatened with punishment if they don't register and let their "advisers" check on what they're applying for.
I would say there's no harm in using the site, if you're careful.  Don't give out personal data such as NI numbers.  And if you're told that it's compulsory to register, point out that it isn't.