By Silvio Pietroluongo

Billboard continues an annual holiday tradition by offering a bounty of year-end charts in this Year in Music & Touring report.

Once again the total number of year-end recaps reaches 251 in our print pages, matching our 2007 roundup, while a total of 416 tallies are available at billboard.com and billboard.biz.

Joining the printed lineup this year are airplay rankings for the following song charts: Mainstream Top 40, Mainstream R&B, Rap, Christian AC, Gospel Songs and Smooth Jazz Songs.

Those additions boost the chart-topping honors this year for acts including Rihanna, Lil Wayne, MercyMe, Marvin Sapp and Paul Hardcastle.

Exclusive to billboard.com and billboard.biz are a host of charts, including Top Alternative Albums, Top Hard Rock Albums, Top Blues Albums, Top Bluegrass Albums, Top Reggae Albums, Top DVD Sales, Hot Triple A Songs and Pop 100 Airplay.

As before, each of the year-end music tallies represent aggregated numbers from the pertinent weekly charts that were compiled for each artist, title and music company.

Most of those numbers are based on data from Nielsen Music, with sales of physical and digital product compiled by Nielsen SoundScan, and radio airplay and digital streams measured by Nielsen BDS. The ringtones/ringmasters categories are based on sales tracked by Nielsen RingScan.

The entire Billboard charts department has a hand in compiling the Year in Music lists. At the center of this effort is chart manager Anthony Colombo, who handles special feature recaps throughout the year, with charts production manager Michael Cusson, associate production manager Alex Vitoulis and associate director of charts Raphael George each playing key roles. Box-
score chart manager Bob Allen compiles the Year in Touring charts.

The rankings for BDS- and SoundScan-based music charts reflect airplay or sales during the weeks that titles appeared on the respective lists during the tracking period. This includes activity during unpublished weeks for those lists that print every other week. The 2008 chart year began with last year's Dec. 1 issue and ended with the Nov. 29, 2008, issue, making it one of the rare years when the chart calendar totals 53 weeks.

Sales or airplay registered before or after a title's chart run are not considered in these standings. That detail, and the December-November time period, account for some of the differences between these lists and the calendar-year recaps that are compiled independently by either SoundScan or BDS.

Artist, imprint, label and distributor categories for all genres reflect accumulated chart performance for all titles on the pertinent chart.

The umbrella "label" categories refer to the distributing labels and/or promotion labels listed on our weekly charts. If only one label appears on a chart listing, that company counts as both "imprint" and "label" for that title.

Certain airplay categories-Mainstream Top 40, Rhythmic, Modern Rock, AC, Adult Top 40, Dance, Mainstream R&B, Adult R&B, Rap, Christian AC, Gospel, Mainstream Rock and Contemporary Jazz-are based on accumulated BDS-monitored plays for each week a song appeared on the chart.

Similarly, the Hot 100 Airplay, Hot R&B/Hip-Hop Airplay, Hot Country Songs and Hot Latin Songs (and the four related Latin-format airplay charts) are determined by adding up the total number of gross impressions, as determined by BDS by cross-referencing exact time of airplay with Arbitron listener data, for each week a track charted.

The Billboard Hot 100, Pop 100 and Hot R&B/Hip-Hop Songs categories reflect accumulated radio and sales points, based specifically on BDS and Nielsen SoundScan data, respectively. For the Hot 100, points from streamed music on AOL and Yahoo also shape the standings.

Hot Soundtrack Singles are the top-ranked Hot 100 songs in cases when the song's success can be directly traced to its inclusion on the soundtrack to a movie or TV show.

For the pop, country and R&B/hip-hop categories that combine data from album and singles charts, formulas have been weighted so that the sales units tallied on the Billboard 200, Top Country Albums and Top R&B/Hip-Hop Albums, respectively, have parity with the specific chart points that construct each week's Billboard Hot 100, Hot Country Songs and Hot R&B/Hip-Hop Songs.

The Dance Club Play rankings are based on an inverse point system, with titles collecting points based on rank for each week they were on the chart.

The publishing categories reflect accumulated points for all charted songs on the applicable weekly charts. If a song is held by more than one publisher, points are divided equally among those companies.

In the Publishing Corporation category, parent companies receive 100% of the points from publishers in which they own at least 50% equity and 25% of the points compiled by publishers that they administer but do not own.

Changes to note in the 2008 recaps:

o Accompanying label listings on the top artists rankings are limited to the label to which each artist is signed. An artist's title count will still include all charting efforts, even those recorded on other labels.

o On the song charts, titles on Virgin, Blue Note and Astralwerks are now part of the Capitol promotion label, while Capitol is the distributing label for Virgin titles on the album charts.

o As of July 1, EMI Music Marketing became the distributor of Welk Music Group labels, including Vanguard and Sugar Hill.

o Universal Latino is now known as Universal Music Latin Entertainment.