Dsp.agency pop-ups aim to redirect your browser to the websites with advertising. Some of these sites can contain some helpful information, whereas the others lead to infecting your PC with potentially unwanted tools. Dsp.agency domain becomes a provider of the link between your browser and third-party resources. Note, that occurrence of any redirections indicate about virus penetration. Most likely your computer got adware or PUP (potentially unwanted program) that is generating such pop-ups at the moment.