MONTREAL -- Canadian companies sought to generate some good-natured brand buzz Monday by releasing their 2013 April Fool's Day ads.

This year's participants included WestJet (TSX:WJA), the Toronto Transit Commission, Lululemon and Boston Pizza.

York University professor Russell Belk says well-executed humour can go viral and attract lots of mainstream media attention, but warns those that miss the mark risk offending.

He says newspapers have run April Fool's stories for decades, but social media can accelerate how widespread the best ads are seen.

Belk points to Calgary-based WestJet, whose tongue-in-cheek ads last year promoted kid-free planes.

This year the airline says it's allowing any kind of animal, including bears, to roam free on board.

Meanwhile, the TTC released a video spoofing annoying things passengers do on the subway. It promoted a personal subway car that allows riders to apply makeup, do personal grooming and use seats for bags and to stretch their legs.

Boston Pizza said it was banning all buns and replacing them with new uses for pizza dough. Several ads on You Tube said it was adding to its menu pizza salad, pizza beer, pizza cake and pizza burgers.

Clothing maker Lululemon said it was introducing lululeather after partnering with local cow farmers who feed their animals organic grass and chia seeds. In addition to Cowabunga yoga pants, it would also offer Moomats for exercise at $208 apiece.

Canadian companies are certainly not alone in taking advantage of April 1. Scores of businesses in Britain and the U.S. have issued news releases or videos.

Google videos promoted new services such as Google Nose that allowed users to scan the web for smells and a new feature on Google Maps that allowed people to search for pirate treasure.

Virgin founder Richard Branson posted on his blog that Virgin Atlantic Airways will soon be offering a glass-bottomed plane service between London and Scotland.