Palermo is the biggest neighborhood in the city of Buenos Aires (although some still argue it is Belgrano). Palermo is divided into so many areas that it is really confusing figuring out which is which.
There are many ways to see Palermo in the map of the city of Buenos Aires but let's just figure out the Northern area: Palermo Viejo.
Palermo Viejo extends from Scalabrini Ortiz to Dorrego between Av. Santa Fe and Av. Cordoba. It used to be a typical, middle class neighborhood but it reinvented itself between 2002 and 2010 and has not stop growing since. The houses in the area got revamped, the neighborhood started to get a better look and a lot of restaurants and boutique hotels started springing up.
Palermo Hollywood is Palermo Viejo's neighbor to it's right, it stretches from J.B. Justo to Dorrego but it is North of Palermo Viejo, starting on Av. Cordoba. It has been baptized "Hollywood" because the offices of TV and movie producers and various TV channels are located there.
Palermo Soho is located to the left of J.B. Justo and starts on Av. Cordoba. It is the Buenos Aires version of NYC's Soho, full of clothing boutiques and big brands. It has home deco stores and is loaded with very nice restaurants and bars. It opens at noon but it starts getting noisier towards night time. There are a lot of boutique hotels in this area as well.
Here is some funny information: the Real Estate boom in the area has been so big that the next door neighbors of Palermo, neighborhoods Chacarita and Villa Crespo have decided to call themselves Palermo Dead and Palermo Queens respectively. More TV producers have set up their offices in Chacarita, around the cemetery therefore restaurants and coffee shops started to get established bringing life to an area that used to be "dead"! Villa Crespo is a big stretch away from Palermo, whoever thought of the name was right! Palermo Queens! getting there is like traveling from NYC into Queens. This area is known for it's outlet stores, mainly.
Hope this helps you figure out the Northern part of Palermo, and here are just two new restaurants that we love in the area:
Unik - Soler St. 5132
Owned by an Argentinean architect who has lived in Paris and Shangai, Unik offers an interesting experience of sophisticated and original dishes produced by Fernando Hara, disciple of Francis Malmann. The atmosphere is hip, colorful and kind of 70's
Sipan - Uriarte 1648
Peruvian - Japanese cuisine. If you were a fan of the other Sipan located in the city's center, this one is even nicer! We love the Pulpo al Olivo and the ceviche of course. 
