Bulk interception differs from targeted interception - bugging a suspect's phone for example - in that it involves the harvesting of large quantities of data from the internet and emails. The data is then sifted and sorted by investigators.
In his review, David Anderson said bulk powers were used by Britain's spy agencies for "cyber-defence, counter-espionage and counterterrorism," as well as investigations into child sexual abuse and organised crime.
Alternative methods of gathering data were available but were "often less effective, more dangerous, more resource-intensive, more intrusive or slower," the review says.
He found there was a case for three kinds of bulk data acquisition:
Bulk interception: The tapping of internet cables by GCHQ to target suspects outside the UK. The review says this is of "vital utility" to the security and intelligence agencies, citing the case of a kidnapping in Afghanistan that would have led to the killing of hostages, if spies had not used these powers.
Bulk acquisition of communications data: The gathering of data about communications but not the content of it. Only disclosed publicly in November last year, for MI5 it has "contributed significantly" to the disruption of terrorist operations, Mr Anderson's report said.
Bulk personal data sets: Databases of personal information, which could include everything from the electoral register to supermarket loyalty schemes, which the security services acquire openly or covertly.
But he expressed some reservations about a fourth practice - bulk equipment interference, which involves hacking into smart phones or computers over "a large geographical area", saying there was "a distinct (though not yet proven) operational case" for it.
Unlike the other bulk powers described in the review, this one has yet to be used, it says.
Mr Anderson also recommended that an independent panel of technical experts be set up to advise about the impact of changing technology "on how MI5, MI6 and GCHQ could reduce the privacy footprint of their activities".